Log body measurements

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations declare the safety profile (not read-only, destructive, idempotent), and the description adds the crucial nuance the annotations cannot: 'Only the values given are replaced; the day's other measurements and its weight are kept.' It also discloses unit conventions and the data.ok response signal, so the destructiveHint is properly scoped.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Four short sentences, front-loaded with the action and scope, followed by units, partial-update semantics, sibling routing, and response meaning. Every sentence carries distinct information with no filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a 10-parameter mutation with an output schema present, the description covers what an agent needs: units, partial-replace behavior, sibling routing, and confirmation signal. Return-value details are correctly left to the output schema.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the baseline is 3, but the description adds genuinely additive semantics absent from the schema: sizes are in the user's size unit (cm unless changed) and fat_percentage is in %. Unit interpretation is not in the property descriptions, so this raises it above baseline.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource with scope: 'Save body measurements for a day.' It even disambiguates from the closest sibling by noting 'Body weight is log_weight', so an agent can separate measurement logging from weight logging without opening either schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives clear context for when this applies (logging measurements for a day) and explicitly routes weight to the alternative tool log_weight. It stops short of naming the read-side siblings (get_body_measurements, get_measurement_history) or stating exclusions, so it is clear but not a full when/when-not map.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.